Crimping seems to be my nemesis: either causing me confusion or frustration!!

Anyway, I've been compiling a shopping list of sorts for my planned expansion into rifle round reloading, based on what is on sale and what people here have suggested.

Given that I will be reloading my bought-and-fired Norma cases, I am sort of decided on a neck sizing die to preserve the fire-formed cases' shape, and micrometer bullet seater that doesn't full cases size (seem to have found a few).

However, I don't seem to have found any rifle crimping dies yet, given the recoil, I'd have thought that bullet creep would be a greater problem than in a handgun.

Is this process included in the bullet seater die, or are rifle rounds simply not crimped, relying purely on neck tension?

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Freedom: Please enjoy responsibly.

Karma. Another word for revolver: because what goes around, comes around!

Sometimes crimping can be done with the seating die- with some makes/models of dies. I can't begin to help you with your endeavor to crimp, as I don't crimp any rifle rounds. Is crimping not covered in the instructions and/or other paperwork that came with the dies?

Also, someone here will likely have your brand of dies here themselves and will likely aske what brand of dies you have.

It's no different than pistol rounds, you can either crimp in one step using the seating die or in a seperate stage. I usually use a Lee Factory crimp die (so much controversy surrounds this die!) to put a very light crimp on mine. Just like with pistol ammo, you'll find people who don't do it at all.

I find that I have to do it on my semi-auto .308, otherwise, I have setback issues when the round contacts the feedramp.

The Lee Deluxe set. This includes a neck sizing collet die, dead length bullet seater, and a full length sizing reloading die (again I'd ignore the full-length). Cheaper at £30, but perhaps a bit less high-spec...

I'm going to forego the RCBS Neck sizing die and Forster micrometer reloading die due to cost and the full length sizing of the Forster.

All mounted on a spare turret for the Lee Cast press.

Quote:

I usually use a Lee Factory crimp die

Do they produce an FCD for .308? I hadn't seen it listed.

Quote:

I don't crimp any rifle rounds.

How is it that the bullets stay put?

__________________

When the right to effective self-defence is denied, that right to self-defence which remains is essentially symbolic.

Freedom: Please enjoy responsibly.

Karma. Another word for revolver: because what goes around, comes around!

If crimping rifle ammo increases accuracy, then one believing such should convince the competitive shooters winning matches and setting records without crimping to do so. These people know better than to crimp rifle ammo case mouths onto bullets. Even the military arsenals learned that crimping .30-06 match ammo case mouths degraded accuracy in semiauto rifles; they quit that back then. None of the military teams handloading ammo for their 7.62 NATO service rifles ever crimped in a bullet; they new better and it wasn't needed. Even commercial and arsenal match ammo used in these match rifles didn't have crimped in bullets; their people knew better.

Crimping adds another huge variable in pressure curve shape and size; not good for accuracy. Crimping also distorts jackets without crimping grooves therefore unbalancing bullets; it ain't uniform all the way around; another bad thing for accuracy.

Do what you want with your reloading tools and techniques. If you have to crimp bullets in for best accuracy, then I think you're doing something wrong with your tools and techniques that crimping partially corrects. Use the right tools the right way and crimping ain't necessary.

If you are shooting a bolt action rifle then for sure no need to crimp. The neck tension is plenty good enough. In handgun cartridges you want to crimp because you are expanding teh case mouth to ease insertion of the bullet. With rifle cartridges you do NOT expand the case mouth so no need to crimp it back down. Magnum revolvers you want a firm crimp to prevent the bullet sliding out and jamming the cylinder.

Plus in the handgun cartridges a little bullet setback can cause a dramatic increase in pressure. Not so in rifle cartridges. The case is much bigger so the ratio of volume displaced by set back is much smaller compared to handgun cases.

Even in a semi-auto crimping often is not necessary. I load for AR15 and M1 Garand and have never had a problem with uncrimped bullets. They do get slammed pretty good on the feedramp so if you want to crimp it may be a good thing to reduce any stoppages. If you load with a bulky slower powder that is compressed (such as Varget or H4895 in .223) then you definitely won't have bullet setback.

I don't think there is any safety concern regarding significant pressure changes. If you are loading for bolt action then no reason to crimp at all. If loading for semi-auto I would not start off crimping and see jhow it works in your rifle first. Chances are it will feed just fine without crimping.

__________________"The ultimate authority ... resides in the people alone. ... The advantage of being armed, which the Americans possess over the people of almost every other nation ... forms a barrier against the enterprises of ambition."

How about crimping in reduced power loads?
I made some 308’s with trail boss loved the round recoil of a 22 but accuracy sucked and they were real dirty
Think it would be worth it to try it with a crimp?

If I read between the lines, I get the vague impression that you don't think rifle round crimping is necessary!!

That's close. Crimping may be necessary for 35+ caliber heavy bullets in light weight rifles for reliability in functioning. But for the rest of them it's harmful to accuracy. Nobody's ever proved to me that crimping rifle bullets really does improve accuracy when such tests are properly conducted with ammo reloaded with proper tools properly set up and used.

That aside, if one gets no worse than 1/3 MOA at 100 yards, 1/2 MOA at 300 or 2/3 MOA at 600 with crimping then go right ahead and do it.

To date, I've not known of anyone who can do that with all shots fired. This is relative to the largest groups shot, not the smallest ones. Any type of bullet-holding setup in case necks will occasionally (rarely?) make a 3-shot group at 100 yards happen. But that's when all the group-changing variables plus shooter ones all add up to do that. When those variables all add up in the other direction, the group may not be covered with a dinner plate.

If crimping rifle ammo increases accuracy, then one believing such should convince the competitive shooters winning matches and setting records without crimping to do so.

Naw, Apples to Oranges at best. The BR guys have a lot of techniques that we as hunters and sport shooters could not or would not do. We don't use high dollar BR rifles and they would not dare use off the shelf Hunting Sporting rifle as we do. No, not even apples to oranges.

BTW, just for your enjoyment I did another accuracy test with the Lee Factory crimp die.

Wanna see?

OK. here goes.

I purchased a K of Midsouth's 55gr Varmint Nightmare JHP bullets for about $90.

I decided to test this new to me bullets in my Colt AR both with a Lee crimp and without. My crimp is what I call a Med-Light.

I chose Win 748 as it has worked well for me in the past with 50-55gr bullets.

I fired five rounds at each target allowing the barrel to cool between each five round group. This is the first set of groups.

I then fired five shot groups from the bottom up starting at 26.5gr and working up the target to 25gr. I did not let the barrel cool at all. The only down time between rounds was loading the mag.

As you can see these bullets shoot damn good for cheap bullets and you can see that the rounds crimped with the LFCD outperformed the non crimped rounds.

5-shot groups have about 55% confidence they are what the stuff will do all the time. And the rounds were not loaded blind to the shooter; he knew which type he was shooting; subconcious issues here.

And we don't know how much of those groups' sizes are cause by human variables. Nor do we know the details of tools and processes used to pass any judgement on them to see if all the good stuff for best accuracy was used and done.

Some competitive shooters use the exact same reloading tools and techniques as hunters and sport shooters and shoot groups just as good as the BR shooters do with rifle hardware costing 4 times as much. A rifle that shoots as good as what the BR ones do doesn't need to cost more than 1 kilodollar. And good scopes can be had for under 400.

Again......

Do what you want with your reloading tools and techniques. If you have to crimp bullets in for best accuracy, then I think you're doing something wrong with your tools and techniques that crimping partially corrects. Use the right tools the right way and crimping ain't necessary.

PS: it would be interesting to see what physical differences there were (are?) between the crimped and non-crimped rounds. Bullet runout, case headspace dimension and spread, chamber headspace, bullet release force, case neck centering on case shoulder, etc.

Steve, that confidence level is based on statistical stuff that was well shown in a graph that's no longer available online. It's based on the simple fact that the more shots one puts in a group, the better it represents the accuracy one can expect for all the ammo with that load.

It parallels an old addage of measuring stuff that, in so many words says, if you don't get the same number every time you measure something, either your ruler is broken or technique is poor. So, if one shoots a few or several groups and they're not all the same size (within 5% for practical shooting accuracy work), they don't realistically define the accuracy of the ammo. The more shots per group there is, the higher ones confidence is it represents the accuracy all that batch of ammo has. Arsenals shoot several dozens of shots per test group with small arms ammo so their confidence level's well over 95%. They measure each shot hole's distance from group center then calculate the mean radius; about the best way to measure accuracy.

I may have saved that image and I'll look for it on my older computer then post it for all to see.

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